1. Field of the Invention
The present invention concerns connector fittings (hereinafter called closure rings) for use with corrugated conduits.
2. Description of the Invention
Corrugated plastic conduits formed with a longitudinal slit are used to protect electrical conductors. Conduits of this kind are highly practical because they avoid the need to insert conductors from one end of the conduit and sliding them along it. Also, these conduits can receive conductors with components attached to their ends, such as electrical connectors, which would not pass through the conduit.
To prevent the conduit from opening along the slit if is curved or deformed, plastic rings are attached to the conduit at various intervals. The plastic rings are comprised of a circular arc shaped part provided at one end with a locking member and at the other end with a hinge member to which is articulated a complementary second circular arc shaped part comprised of a free end which is provided with a locking member complementary to the member on the first part. The internal surface of the ring is comprised of at least one rib adapted to cooperate with a groove formed between the corrugations on the conduit. These rings are usually molded in one piece from a plastic material, the hinge comprising a plastic strip joining the two circular arc shaped parts.
A disadvantage of these rings is that the strip forming the hinge must necessarily be thin and therefore mechanically weak so that they often break, the result being that the ring does not remain attached to the conduit.
It has been proposed to provide means for locking the parts adjoining the hinge when the ring is closed, but these proposals have proved to be too complex and impractical to mold.
There is also known in the prior art (see U.S. Pat. No. 4,443,031) a ring molded in one piece from a plastic material, having two complementary portions defining between them a cylindrical body joined by a strip forming a hinge, one portion comprising at its free end a first bar with an inwardly facing hook and the second portion with a hook facing the same way as the first hook, with openings being provided in each portion to receive the corresponding hook.
An arrangement of this kind has various disadvantages. The hinge is necessarily wide so that the second hook can be inserted into the corresponding opening in the first portion, with the result being that when the ring is closed the hinge forms a bead and the fitting cannot be used in particularly small or narrow places.
Also, the interior surface of the ring comprises ribs for cooperating with the corrugations on the conduit and if traction is applied to the conduit there is a tendency for the hooks to separate from the openings.
An object of the present invention is to remedy these disadvantages.